Stumbled across this document today. http://www.scribd.com/doc/116315083/Cameron
As part of the lawsuit between Cameron and Morawaski (which just concluded in Cameron's favour), James Cameron put out this declaration on how the film was original. It goes right back to his childhood and explains where all his early ideas came from; makes for some interesting reading if you stick with it. Shame the attached images aren't on there, I would have loved to see the 40 year old sketch of his that became the concept for the Pandoran jungle.